The onset and progression of various ocular complications are being investigate as well as methods for their potential pharmacological control. Specifically, relationships between diabetes and galactosemia-induced retinopathy, cataract, keratopathy, and changes in pupil function, iris and ciliary process structure and the interactions of the enzymes aldose reductase and aldehyde reductase are being investigated. Methods for either delaying or preventing the onset and progression of these complications through the pharmacological control of these enzymes are also being developed. Events leading to the formation of several types of cataracts are also being studied as well as methods for controlling the onset of these cataracts through pharmacological intervention.